Just tried F# on Visual Studio Team System last night. It ran smoothly... so far.
The first thing I tried is a little Fibonacci code...

Then testing some simple codes below...

For you who came from object-oriented background, this language might looks like an alien language. But it is not that difficult to familiarize yourself with these syntaxes. Trust me.
If you want to have a taste of F# just follow these easy steps :
- Remove any previously installed version of Microsoft Research F#.
- Install Microsoft Visual Studio. (I tried it on Team System 2008)
- Install Microsoft Research F#. You can download it here.
- After all steps above are done. Open your Visual Studio.
- Choose Tools, then Add-In Manager.
- Check "F# Interactive for Visual Studio" check-box.
- Try it, click New Projects >> Other Project Types >> F# Projects.
- Have fun!
Just want you to know, as Mr. Somasegar has stated earlier here, F# will be the first class citizen of .NET in the future. That means F# will get the same support as C#, VB .NET, and C++. F# itself is actually a multi-paradigm programming language. It supports object-oriented programming as well, but it was designed mainly for functional programming.
Why is functional programming cool?
I will write that later because I have to prepare for my speech tomorrow.